Git commits in Moodle 3.5.2 by Didier 'OdyX' Raboud

commit cb4bb6efc5c39a6e9d8886fbd7faab28a2595ecd
Author: Didier 'OdyX' Raboud <didier.raboud@liip.ch>
Date:   Tue, 19 Jun 2018 23:12:23 +0800
Tag:    v3.5.2

MDL-62753 shibboleth: Logout: fix DB sessions kill